1. Field of the Invention
The present invention relates to a multilayer molded article and a method for producing the same. In particular, the present invention relates to a thermoplastic resin molded article having a skin material layer, which article has good appearance and is used as an automobile interior panel or an electric appliances, and a method for producing such molded article.
2. Description of the Related Art
There are widely known high-grade molded articles which have improved beauty and softness by laminating a skin material thereon. As the skin material, a film or sheet of soft polyvinyl chloride or a thermoplastic elastomer can be used.
As a method for producing a multilayer molded article having a skin material, there is a method comprising forming a molded article of a thermoplastic resin by a conventional molding method such as injection molding and then forming the skin material on the molded article by, for example, vacuum molding, or simultaneously forming the molded article and the skin material with laminating the skin material to the article with an adhesive.
Alternatively, the multilayer molded article can be produced by placing the skin material in a mold, closing the mold, then injecting a molten thermoplastic resin in a mold cavity through a gate of the mold to laminate the resin with the skin material, cooling the mold and opening the mold to remove the molded article. In connection with this method, it is known to use a mold having ornamental designs on its inner wall so as to transfer such designs to a surface layer of a skin material comprising the surface layer and a foam layer and improve the appearance of the molded article (cf. Japanese Patent Kokai Publication No. 83633/1984).
However, in the method comprising supplying a thermoplastic resin melt onto the skin material which comprises the surface layer and the foam layer so as to transfer the ornamental designs of the mold to the skin material, since molding conditions including a mold temperature, a temperature of the thermoplastic resin and a molding pressure are very severe, the foam layer is crushed to a large extent and defective moldings are often found.
When the skin material having no backing foam layer is used, the skin material is strongly pressed against the mold by the thermoplastic resin melt at high temperature and high pressure, its surface is discolored and designs of the skin material are deformed so that the appearance of the molded article tends to be deteriorated.